BIODIESEL & SVO DISCUSSION FORUMS





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Dgs thanks, I look forward to your results


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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Hi Biotom,
quote:
Originally posted by Biotom:
Dgs, if you could list the temperature of the air as well as the RH maybe a table could be put together that would show ppm moisture and negate the requirement of using SB or KF...
An excellent Idea! I am glad you thought of it!






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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It seemed from the beginning of the discussion that the humidity in the headspace over the biodiesel was being measured, and that dried make-up air for the extraction fan was provided by the air source for the 'bubbler' presumably a compressor.

Therefore, unless the extraction fan is pulling ambient air into the headspace, the ambient humidity has no effect.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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Hi john galt.

quote:
Originally posted by john galt:
It seemed obvious from the beginning of the discussion that the humidity in the headspace over the biodiesel was being measured, and that dried make-up air for the extraction fan was provided by the air source for the 'bubbler' presumably a compressor.

Therefore, unless the extraction fan is pulling ambient air into the headspace, the ambient humidity has no effect.
The humidity in the headspace over the biodiesel is not being measured.
The sensor is mounted somewhere outside the reactor in the exhaust stream. "Sam, the probe is in the air above the extraction fan,...
It depends on how the exhaust is constructed and where the measuring device is mounted.
You are the first person to question whether there is contamination of the exhaust being measured.

"Basically the dryer is a plywood disc that sits on top of the processor/wash tank. On top of the disc is a 10-15 litre plastic drum with a sealed lid. on top of the drum is something like a tuppaware sandwich box with about 2" of self-indicating silica gel inside. Small holes are drilled in the lid of the sandwich box and the base (through the top of the 15 litre tub)
inside the tub is an aquarium bubbler, with the pipe going down to the tank bottom. At the back of the plywood disc is a 4" computer fan pulling air out of the headspace, driven from a small led transformer also inside the tub. All joints, lead exits are sealed with silicone.

The air pump can only pull air that has come through the silica gel, as the air goes down the line it gets warmed by the biodiesel (50 to 65 degs)"




At the moment my main concern is that Posting the Relative humidity without telling the temerature of the air is meaningless in this situation

This message has been edited. Last edited by: Tilly,






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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quote:
Originally posted by john galt:
It seemed from the beginning of the discussion that the humidity in the headspace over the biodiesel was being measured, and that dried make-up air for the extraction fan was provided by the air source for the 'bubbler' presumably a compressor.

Therefore, unless the extraction fan is pulling ambient air into the headspace, the ambient humidity has no effect.


Correct john.

----------------------------------------------------------------------------------------------------
originally posted by Tilly
At the moment my main concern is that Posting the Relative Humidity without telling the temperature of the air is meaningless in this situation.
-----------------------------------------------------------------------------------------------------

Don't be concerned Tilly, the method works, you will see.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs
quote:
Originally posted by Dgs:
[quote]You seem to have a very vague understanding of what Relative Humidity is./QUOTE]
I undestand this meaning very well thank you.
Are you sure?
If that is the case, it leaves me even more perplexed that you never mention the temperature of the air when you give a Relative Humidity reading.
You just give the temperature of the biodiesel which is meaningless when it comes to Relative Humidity.

For instance, on August 9 this year you posted on the site you linked to:
When the temperature was at 40degs the dryer was started. Within a few minutes the R/H had dropped from an ambient reading of 57% to 52%. “

No mention of the Air Temperature which is all-important when talking about Relative Humidity. Just the temperature of the biodiesel which is irrelevant to the Relative Humidity.
At that point the Air temperature was still increasing.
Obviously the drop in Relative Humidity over those first few minutes would have had virtually nothing to do with the biodiesel becoming dryer, it was just the result of the air warming up that was blowing across your humidity sensor.

Even in your recent reply to Biotom in this thread you are still talking about the temperature of the biodiesel, not the temperature of the air:
”Tom, That is exactly what I do, as the biodiesel is held at 65degs the exiting air does not really alter very much in temperature.“
This indicates that you do not really understand how important Air Temperature is when talking about relative humidity in this situation.

Let me refresh your memory:
”Relative humidity is the amount of moisture in the air compared to what the air can "hold" at that temperature.”

If you need this explained further, just ask.






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post



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I think you are still missing the point Tilly.

No matter how much the temperature affects the reading, the biodiesel moisture ALSO does.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs:
I think you are still missing the point Tilly.

No matter how much the temperature affects the reading, the biodiesel moisture ALSO does.
I am afraid it is you who is missing the point.
It is the moisture in the air and the temperature of the air that determines Relative Humidity.

”Relative humidity is the amount of moisture in the air compared to what the air can "hold" at that temperature.”






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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quote:
Originally posted by Dgs:
Tom, That is exactly what I do, as the biodiesel is held at 65degs the exiting air does not really alter very much in temperature.

I have only so far checked the 3x R/H levels with my S/B. The 26% R/H is what I usually aim for as when I have checked all the samples dried down to this level with my S/B all the results have been between 110 and 130ppm.

The results have been very consistant and as you say it eliminates the need for checking every batch.

Over the next few weeks I will graph the results and post it, will be interesting. There are a few others in the UK that now use this method of checking the water by virtue of R/H as the biodiesel is drying.

Dgs, where did the graph of results go?
Was there ever a chart made of
different temps of air, relative humidity and ppm water in bio? I would like to use the method without heating the bio but apparently that means a different RH "goal" to reach 250ppm or other. Can one extrapolate or calculate using 65C and 26%RH to a different bio/oil temp?
 
Location: Saint Paul, MN. | Registered: September 17, 2007Reply With QuoteReport This Post
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quote:
Originally posted by sooty:
quote:
Originally posted by Dgs:
Tom, That is exactly what I do, as the biodiesel is held at 65degs the exiting air does not really alter very much in temperature.

I have only so far checked the 3x R/H levels with my S/B. The 26% R/H is what I usually aim for as when I have checked all the samples dried down to this level with my S/B all the results have been between 110 and 130ppm.

The results have been very consistant and as you say it eliminates the need for checking every batch.

Over the next few weeks I will graph the results and post it, will be interesting. There are a few others in the UK that now use this method of checking the water by virtue of R/H as the biodiesel is drying.

Dgs, where did the graph of results go?
Was there ever a chart made of
different temps of air, relative humidity and ppm water in bio? I would like to use the method without heating the bio but apparently that means a different RH "goal" to reach 250ppm or other. Can one extrapolate or calculate using 65C and 26%RH to a different bio/oil temp?

FOUND IT!
www.biopowered.co.uk/forum/ind...p/topic,2538.30.html
7th post down. Thanks Dgs.
 
Location: Saint Paul, MN. | Registered: September 17, 2007Reply With QuoteReport This Post
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Pleased you have found it sooty.

Cheers, Dave.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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